There are known information input devices that utilize touch panels. Examples of such information input devices include those utilized as ATM's, and those utilized at ticket vending machines at train stations. There is also a known table shaped touch panel, as a newer type of information input device (refer to FIG. 2 and FIG. 3 of International Publication No. WO01/40923, for example). In this touch panel, images are displayed within an area surrounded by a sensor section of the touch panel. The touch panel is configured to accept input of necessary information by touching (contacting) portions of the image display area. The table shaped touch panel is used in cases that a plurality of people surround the table to conduct meetings and necessary information is to be displayed during the meetings, for example. The position of a finger that touches the touch panel is detected by the sensor section, and input of information corresponding to the position is enabled. At the same time, desired information is displayed within the image display area of the touch panel.
There is another conventional type of touch panel, in which a button panel created by software and a main panel are displayed on an LCD (Liquid Crystal Display) (refer to FIG. 4 of Japanese Unexamined Patent Publication No. 7(1995)-110742, for example). In this type of touch panel, detection of contact positions is enabled in both the button panel region and the main panel region.
In addition, the present applicant has proposed an acoustic type contact detecting apparatus as a touch panel (refer to FIG. 1 of Japanese Unexamined Patent Publication No. 2004-164289).
The conventional touch panels disclosed in International Publication No. WO01/40923 and Japanese Unexamined Patent Publication No. 2004-164289 are not provided with external switches, such as those for booting up a PC (Personal Computer) or for adjusting the screens thereof. The touch panel disclosed in Japanese Unexamined Patent Publication No. 7-110742 is provided with the button panel in addition to the main panel. Therefore, input corresponding to operations of external switches can be performed by operating the button panel. However, a portion of the display surface of the LCD is utilized as the button panel, and accordingly the area of the display region for necessary information is decreased. If a display region having a sufficiently large area is to be secured, there is a problem that the entire device will become large.